The Integer datatype has been replaced with the int datatype in previous version of designer, so it is now not possible to set the datatype to integer when creating new models. The integer datatype is however still supported in designer for legacy purposes (importing old projects, vdbs etc). Using integer in deployed vdbs results in some issues when reimporting (e.g. TEIIDDES-2460).

As suggested here, designer should issue a validation warning for each integer use and should also provide a quick fix to convert all the usages of integer to int.